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#include "game.h"
#include "sys.h"
#include <SDL3/SDL.h>
#include <GL/glew.h>
#define DEBUG 1
typedef struct {
SDL_Window *window;
i32 width;
i32 height;
SDL_Renderer *renderer;
u64 last_counter;
f32 dt;
} sdl_context_t;
static sdl_context_t init_sdl(i32 width, i32 height, i32 debug)
{
sdl_context_t ctx = {0};
ctx.width = width;
ctx.height = height;
SDL_Init(SDL_INIT_VIDEO);
u64 flags = SDL_WINDOW_OPENGL;
SDL_CreateWindowAndRenderer("breakout", ctx.width, ctx.height, flags, &ctx.window, &ctx.renderer);
if (debug)
SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, SDL_GL_CONTEXT_DEBUG_FLAG);
SDL_GLContext glctx = SDL_GL_CreateContext(ctx.window);
SDL_GL_MakeCurrent(ctx.window, glctx);
SDL_GL_SetSwapInterval(0);
ctx.last_counter = SDL_GetPerformanceCounter();
glewInit();
return ctx;
}
static void process_sdl_key(input_t *input, i32 scancode, i32 pressed)
{
switch (scancode) {
case SDL_SCANCODE_ESCAPE:
input->escape.current = pressed;
break;
case SDL_SCANCODE_RIGHT:
input->right.current = pressed;
break;
case SDL_SCANCODE_LEFT:
input->left.current = pressed;
break;
case SDL_SCANCODE_SPACE:
input->space.current = pressed;
break;
default:
break;
}
}
static void process_sdl_events(game_t *game)
{
SDL_Event event;
while (SDL_PollEvent(&event)) {
switch (event.type) {
case SDL_EVENT_KEY_DOWN:
case SDL_EVENT_KEY_UP:
process_sdl_key(&game->input, event.key.scancode, event.key.down);
default:
break;
}
}
}
static f32 get_elapsed(u64 last_counter)
{
u64 frequency = SDL_GetPerformanceFrequency();
u64 current_counter = SDL_GetPerformanceCounter();
return (f32)(current_counter - last_counter) / (f32)frequency;
}
static void lock_framerate_sdl(sdl_context_t *ctx, i32 fps)
{
f32 elapsed = get_elapsed(ctx->last_counter) * 1000.0f;
f32 target = 1000.0f / (f32)fps;
f32 sleep = target - elapsed;
if (sleep > 0)
SDL_Delay((u32)sleep);
do {
elapsed = get_elapsed(ctx->last_counter) * 1000.0f;
} while (elapsed < target);
ctx->dt = get_elapsed(ctx->last_counter);
ctx->last_counter = SDL_GetPerformanceCounter();
}
static void fps_info(f32 dt, i32 again)
{
static f32 time = 0;
static i32 lastsec = 0;
static f32 sumdt = 0;
static i32 sumfps = 0;
static f32 frame_count = 0;
time += dt;
sumdt += dt;
sumfps += (i32)(1.0f / dt);
frame_count++;
i32 sec = (i32)time;
if (sec != 0 && sec % again == 0) {
if (lastsec != sec) {
f32 mean_dt = sumdt / frame_count;
f32 mean_fps = sumfps / frame_count;
info("time: %d dt: %f fps: %f", sec, mean_dt, mean_fps);
lastsec = sec;
sumdt = 0;
sumfps = 0;
frame_count = 0;
}
}
}
i32 main(void)
{
sdl_context_t ctx = init_sdl(1600, 800, DEBUG);
game_t game = init_game(ctx.width, ctx.height);
while (game.running) {
process_sdl_events(&game);
process_input(&game);
update_game(&game, ctx.dt);
update_input(&game.input);
lock_framerate_sdl(&ctx, 60);
fps_info(ctx.dt, 10);
render_game(game);
SDL_GL_SwapWindow(ctx.window);
}
return 0;
}
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